Thursday, February 6, 2014

Agent Orange and Cancer

About 3 million Americans served in the
armed forces in Vietnam and nearby areas during the 1960s and early
1970s, the time of the Vietnam War. During that time, the military used
large amounts of mixtures known as defoliants, which are
chemicals that cause the leaves to fall off plants. One of these
defoliants was Agent Orange, and some troops were exposed to it. Many
years later, questions remain about the lasting health effects of those
exposures, including increases in cancer risk.

This article offers a brief overview of the
link between Agent Orange and cancer. It does not offer a complete
review of all evidence – it is meant to be a brief summary. It also
includes some information on benefits for which Vietnam veterans exposed
to Agent Orange may be eligible.During the Vietnam War, US military forces
sprayed millions of gallons of herbicides (plant-killing chemicals) on
lands in Vietnam, Laos, and other nearby areas to remove forest cover,
destroy crops, and clear vegetation from the perimeters of US bases.
This effort, known as Operation Ranch Hand, lasted from 1962 to 1971.

Different mixes of herbicides were used, but most were mixtures of 2 chemicals that were phenoxy herbicides:

2,4-dichlorophenoxyacetic acid (2,4-D)

2,4,5-trichlorophenoxyacetic acid (2,4,5-T)

Each mixture was shipped in a chemical
drum marked with an identifying colored stripe. The most widely used
mixture contained equal parts 2,4-D and 2,4,5-T. Because this herbicide
came in drums with orange stripes, it was called Agent Orange. Today,
Agent Orange refers generally to all the phenoxy herbicides sprayed at
the time. (Other types of herbicides were also used, including cacodylic
acid and picloram.)

The 2,4,5-T in Agent Orange was contaminated
with small amounts of dioxins, which were created unintentionally
during the manufacturing process. Dioxins are a family of dozens of
related chemicals. They can form during the making of paper and in some
other industrial processes. The main dioxin in Agent Orange,
2,3,7,8-tetrachlorodibenzo-p-dioxin, or TCDD, is one of the most toxic.

After a study in 1970 found that 2,4,5-T
could cause birth defects in lab animals, the use of 2,4,5-T in Vietnam
was stopped. A year later, all military herbicide use in Vietnam ended.
During the 1970s, some veterans returning from Vietnam began to report
skin rashes, cancer, psychological symptoms, birth defects in their
children, and other health problems. Some veterans were concerned that
Agent Orange exposure might have contributed to these problems. These
concerns eventually led to a series of scientific studies, health care
programs, and compensation programs directed to the exposed veterans.

A large class-action lawsuit was filed in
1979 against the herbicide manufacturers, and was settled out of court
in 1984. It resulted in the Agent Orange Settlement Fund, which
distributed nearly $200 million to veterans between 1988 and 1996.

Although there is now quite a bit of
evidence about the health effects of Agent Orange, many questions have
not yet been answered.